S1 actress and AV male actor couple engage in a "swapping" theme, with "Kuramochi Yua" appearing as the first installment. Two participating couples, whose relationships have become severely strained beyond repair, boldly decide to completely switch partners. Amidst tangled emotions of jealousy, confusion, and excitement, they experience intense partner swapping. Through unfamiliar physical sensations and new relationship dynamics, they discover the true nature and hidden charms of their partners—an unusual experience unlike any other. S1 awaits your swap requests.